1. Technical Field
This disclosure relates to camera lens length measuring systems, and particularly to a system and a method for measuring a total track length of a telescopic camera lens.
2. Description of Related Art
Camera modules are generally installed in mobile telephones, personal digital assistants or other portable electronic apparatuses to record memorable moments due to their convenience and practicality. The designs of the portable electronic apparatuses have evolved toward lightweight and compactness tendency, so have the currently popular digital camera modules.
The digital camera module generally includes a lens, a sensor for converting light transmitted through the lens into electronic image signals, and a motor for driving the lens into telescopic movement. Most portable electronic apparatuses equipped with camera modules have a limited internal space, in such a condition, a total track length (a distance between a first surface of the lens and a film surface of the sensor) of the lens need to be relatively short. However, the short total track length of the lens makes it difficult for the camera module to achieve a high optical performance while being compact, especially during the telescopic movement of the lens.
What is needed, therefore, is a system and method for measuring a total track length a lens, which is capable of identifying whether the camera module with the lens is suitable for the portable electronic apparatuses while maintaining a high optical performance.